Impeller for a fan



FIG. 1 is a perspective view of an impeller for a fan showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in FIG. 7 depict parts of the impeller for a fan that form no part of the claim. The surfaces shown between the solid lines and the broken lines in FIG. 7 form no part of the claimed design. 

CLAIM The ornamental design for an impeller for a fan, as shown and described. 